Papers and documents on data erasure techniques?

Hello everyone, i would like to hear fro you about some readings i can look for about data erasure/data destruction techniques on different types of media.

I know that it's a pretty basic topic, but i was assigned such topic in my forensics course, so i was looking for some documents explaining things in depth, so any kind of paper or document from wich i can collect informations from is welcome.

thnx in advice )